TRANQUEBAR, a seaport town in the Tanjore district of Madras presidency, India, in 11° 1′ 37″ N. lat. and 79° 55′ E. long. In the 17th century it belonged to the Danes; it was taken by the British with other Danish settlements in 1807, but restored in 1814, and finally purchased in 1845 for a sum of 20,000. In Danish times Tranquebar was a busy port, but its prosperity has fluctuated considerably of late years, and is now at a very low ebb. It was the first settlement of Protestant, missionaries in India, founded by Ziegenbalg and Plutschau (Lutherans) in 1706; and as a mission station it still retains its importance.